<template>
     <div class="todo-footer">
    <label>
      <input type="checkbox" v-model="isAllCheck">
    </label>
    <span>
      <span>已完成{{completeSize}}</span>/全部{{todos.length}}
    </span>
    <button class="btn btn-danger" v-show="completeSize>0" @click="deleteCompleteTodos">清除已完成任务</button>
  </div>
</template>
<script>
export default {
    props:{
        todos:Array,
        deleteCompleteTodos:Function,
        selectAllTodos:Function
    },
    computed:{
        completeSize(){
            return this.todos.reduce((preTotal,todo)=>preTotal+(todo.complete?1:0),0)
        },
        isAllCheck:{
            get(){

                return this.completeSize===this.todos.length&&this.completeSize>0
            },
            set(value){
                this.selectAllTodos(value)
            }
        }
    }
}
</script>
<style>
.todo-footer {
    height: 40px;
    line-height: 40px;
    padding-left: 6px;
    margin-top: 5px;
  }

  .todo-footer label {
    display: inline-block;
    margin-right: 20px;
    cursor: pointer;
  }

  .todo-footer label input {
    position: relative;
    top: -1px;
    vertical-align: middle;
    margin-right: 5px;
  }

  .todo-footer button {
    float: right;
    margin-top: 5px;
  }
</style>


